1. Field of the Invention
The present invention relates generally to acoustic earmuff devices and is more particularly concerned with a novel articulated earmuff-to-headband attachment construction therefor.
For purposes of the present invention an "acoustic earmuff device" is intended to mean a device broadly comprising a generally U-shaped resilient headband to the interior of each free end portion of which there is affixed an earmuff comprising a rigid earcup element. Such devices find applications as hearing protectors for workers in noisy environments and, when at least one earmuff is equipped with a suitable electromechanical transducer, or sound conducting tube, as earphone elements of communication systems. The resilient headband is generally adapted, such as by appropriate sizing design and selection of materials of construction thereof, to bias the earmuffs against the head of the wearer, thereby to secure them thereto. In view of the variable head sizes and shapes encountered in the user population, it is desirable to provide an earmuff-to-headband attachment construction which is pivotally articulated so as to allow the earmuffs to conform to the head shape of any user under the urging of the headband and to thereby effectuate a competent sealing engagement of the open ends of the earmuffs to the head. It is also desirable to provide the articulated attachment construction with sufficient range of motion as to allow the acoustic earmuff device to be worn with good effect with the headband in any of the over-the-head, behind-the-neck or below-the-chin positions.
2. Description of the Prior Art
The prior art discloses several types of articulated earmuff-to-headband attachment constructions which serve the aforementioned purposes to a greater or lesser degree. In British Patent Specification No. 1,347,824, published Feb. 27, 1974, to Exel Oy, there is disclosed a ball joint arrangement for adjusting the inclination of each earmuff relative to the headband. The ball element of the joint is contained in a spherical socket formed in the interior of the back wall of the earcup element of the earmuff. A stub extending inwardly from an end portion of the headband traverses an external aperture in the back wall of the earcup and is fitted into that portion of the ball exposed to the exterior of the earcup. The ball is secured into the internal spherical socket of the earcup back wall by means of an internal plug and star washer combination. While the earmuff-to-headband attachment construction of this patent publication appears to result in a good range of articulation of the earmuff relative to the headband, it is a somewhat complicated construction in terms of its fabrication and assembly and, moreover, does not result in acoustic isolation of the headband from the earmuff. Thus, sound wave or vibrational energy imparted from the external environment to the headband appears to be susceptible of conduction into the earcup elements through the disclosed ball joint construction.
In British Patent Specification No. 1,355,052, published May 30, 1974, to Robert Ian Johnson et al., there is disclosed a hearing protector comprising a pair of resilient, ear-insertable, one-piece, multiply-flanged earplugs affixed to inwardly directed ends of a resilient, generally U-shaped tubular headband. FIG. 4 and in the text relevant thereto disclose a direct swivelling attachment of each earplug to the headband comprising a ball-shaped inwardly directed free end of the headband fitted into a receiving socket formed in the outboard end of the earplug. FIG. 6 and the text relevant thereto disclose an attachment of the earplugs to the headband comprising a rigid connecting piece interposed between the headband and earplug, said connecting piece having a cylindrical outboard end of a dimension adapted to be tightly and rigidly fitted within a tubular inwardly turned free end of the headband and a double-barbed inboard end which is engaged within a socket provided in the outboard end of the earplug. The association between the earplugs and the headband in the construction of FIG. 6 is not said to be articulated and it does not appear to be susceptible of such character because the outboard end of the intermediate connecting piece is tightly affixed into the tubular end of the headband and because the linearly separated dual barbs of the inboard end of the connecting piece are both shown to be tightly captured in the resilient outboard socket of the earplug. Moreover, the various constructions of this publication are said to serve the principal function of urging the earplugs into the external auditory meatuses of the wearer under the influence of the headband. In the case of acoustic earmuff devices of the type concerned in the present invention, however, there is no invasive entry of any portion of the device into the ears of the user.
West German Patentschrift DE No. 25 16 709, laid open on Oct. 28, 1976, to Erwin Martin Heberer, discloses a ball-and-socket type attachment of acoustic earmuffs to a resilient headband. The ball element of the attachment is defined at the free inboard end of an inwardly directed stud affixed to the end of the headband. The socket element of the joint is contained in an externally tapered collet which comprises a plurality of split fingers at the outboard end thereof. Said fingers are sprung open and the ball inserted into the socket lying thereunder. Once the ball has been so inserted and seated within the outboard end of the collet, the inboard end thereof, which is multiply slotted and externally toothed, is forced into a close fitting tapered collet seat formed through the back wall of the earcup element of the earmuff, the external teeth of the collet splaying open upon entry of the inboard end thereof into the earcup chamber and thereby conjointly locking the collet into place within the tapered collet seat and securing the ball within socket underlying the outboard fingers of the collet. While the particular attachment construction disclosed in West German Patentschrift DE No. 25 16 709 appears to provide for good articulation between the earmuffs and the headband, said construction appears to suffer from a lack of acoustic isolation between the headband and the earmuffs. The headband, earcups and collet elements of the construction all appear to be composed of rigid sound conductive materials and are in physical contact in the assembled condition of the construction. Therefore, sound or vibrational energy which may be imparted to the headband from the external environment is provided with a conductive pathway into the rigid earcup elements of the construction.
In accordance with the present invention, there is provided a novel pivotally articulated earmuff-to-headband attachment construction having the attibutes, severally or in combination, of: simplicity of design, ease of fabrication, ease of assembly, pivotal articulation of sufficient range as to allow the earmuffs of acoustic earmuff devices so equipped to readily conform to the head of the user and which construction additionally provides substantial acoustic isolation of the earmuffs from the headband. Other benefits and advantages of the present invention will in part be obvious and will in part appear hereinafter.